This plan sounds a bit like a science fiction scenario where alien devices were planted in the ground thousands of years ago only to be awoken at some predetermined date to destroy the world. Only in this case it's the scientists at Defense Advanced Research Projects Agency who want to develop a system of submersible pods that could reside in the world's oceans (presumably not in anyone's territorial waters) and be activated for any number of applications days, months or even years later.

The Upward Falling Payload (UFP) project, as DARPA calls it, centers on pre-deploying deep-ocean nodes years in advance in forward areas which can be remotely commanded to launch to the surface. "The objective of the UFP program is to realize a new approach for enabling forward deployed unmanned distributed systems that can provide non-lethal effects or situation awareness over large maritime areas," DARPA stated.

Depending on the specific application, DARPA said UFP systems would provide "a range of non-lethal but useful capabilities such as situational awareness, disruption, deception, networking, rescue, or any other mission that benefits from being pre-distributed and hidden. An example class of systems might be small unmanned aerial vehicles that launch to the surface in capsules, take off and provide aerial situational awareness, networking or decoy functions."

"Almost half of the world's oceans are more than four kilometers deep. This provides considerable opportunity for cheap stealth. The vastness and depth make retrieval costs prohibitive. Despite this, the UFP program is specifically not a weapons program, and the risks to losing any single node will be minimal," DARPA said

The UFP system is envisioned to consist of three key subsystems, DARPA says:

The 'payload' which executes waterborne or airborne applications after being deployed to the surface

The UFP 'riser' which provides pressure tolerant encapsulation and launch (ascent) of the payload

The UFP communications which triggers the UFP riser to launch. A multi-phase effort is envisioned to design, develop, and demonstrate UFP systems.

DARPA said it is looking for proposals in three key areas for developing the program: Communications, deep ocean 'risers' to contain the payloads, and the actual payloads. DARPA envisions technical communities that conduct deep-ocean engineering from the telecom and oil-exploration industry to the scientific community with insights into signal propagation in the water and on the seafloor would be interested in the project.